Magnetic Resonance Imaging (MRI) has become the gold standard in the imaging of many soft tissues, osseous and joint conditions, but to date there has been limited success in harnessing this excellent imaging modality for interventional procedures. At the same time, MRI poses formidable research challenges by limited access to the patient and a strong magnetic field that prevents the use of conventional materials and electronic equipment. Currently, no exigent technical solution exists to assist MRI-guided needle placement procedures in an accurate, simple, and economical manner. The objective of the proposed research program is to make diagnostic closed high-field MRI scanners available for guiding needle placement in musculoskeletal and spinal interventions. Our approach is to apply image overlay technique to make an MR image virtually float inside the patient in correct alignment and magnification, as if the operator had "MRI vision" to virtually slice through the body. The technical hypothesis is that MR image overlay guidance is suitable for a variety of needle-based interventional procedures and it allows for appropriate procedural accuracy and consistency in musculoskeletal and spinal interventions on conventional closed high-field MRI scanners. The specific aims toward proving our technical hypothesis are the following: (1) Develop a clinically adequate and integrated image overlay system to guide needle insertion on high-field (1.5T-3T) closed MRI scanners. (2) Refine procedural workflow and perform technical validation of the system on phantoms and human cadavers. (3) Perform clinical system performance evaluation trial on human subjects in joint arthrography, MSK biopsy (sarcoma), vertebral biopsy, and disk space aspiration procedures. The potential societal benefit of the proposed research is significant. Our long-term objective is to produce generally applicable technology for in-room MRI-guided needle placement. As MRI is becoming gradually affordable, the MR image overlay technique may facilitate a wide array of diagnostic and therapeutic interventions involving percutaneous needle insertion. An effective, simple, and affordable guidance system would provide greater access for facilities using the current install base of magnets. It can also reduce variability among practitioners, facilitate training, and serve as a research validation tool by providing precisely placed minimally invasive percutaneous conduit under MR guidance. [unreadable] [unreadable] [unreadable]